[vlc-devel] [PATCH] swscale: fix compilation

[Vittorio Giovara]

On Fri, Feb 26, 2016 at 9:20 AM, Derek Buitenhuis
<derek.buitenhuis at gmail.com> wrote:
>> -#define FF_API_SWS_CPU_CAPS    (LIBSWSCALE_VERSION_MAJOR < 4)
>
> LIBSWSCALE_VERSION_MAJOR was 3 at the time. The commits were in the
> wrong order, apparently. The version bump[1] came many commits later,
> instead of before, so if one were to check out a commit in between there,
> it would be broken.

The version bumps have always been done *after* removing deprecated
APIs, it's a standard procedure that the project(s) have been
following: make the bump after the libraries have been modified to
alert users that there have been ABI-breaking changes. I am not sure
why you're even bringing up this here in the first place given the
month-long review the set had received.

If one checks out a commit in a *development* tree rather than in
stable branch he or she must know what he is doing.

> That said, I am unaware of any actual release in Libav or FFmpeg which
> lies in between. the n2.9-dev tag is not a release.

I think this is the actual problem, ffmpeg tagged the tree during an
unstable commit series for whatever reason, and this led users believe
that tag was ok to use. While I can't understand why a user would
check out that particular tag, I find even stranger why that
particular commit was tagged in the first place. After all would you
ever tag an unstable ABI-breaking commit?

If my point is still not clear, I believe downstream apps should not
introduce additional changes in their code for upstream inability of
properly tagging their software.
-- 
Vittorio